Cable terminal



Patented Nov. 13, 1934 UNITED STATES PATENT OFFICE CABLE TERMINAL Jersey Application March 1, 1932, Serial No. 595,992

6" Claims.

This invention relates to an improvement in cable terminals for oil filled cables and provides a terminal of simple construction and yet possessing great mechanical strength so as to be capable 5 of withstanding internal pressures up to eight hundred pounds or more, for instance. Inasmuch as these terminals are filled with oil and the dielectric strength of the oil increases with increase in pressure a terminal which may with safety be placed under higher pressure than heretofore offers an advance over previous structures.

Referring to the accompanying drawing which shows an embodiment of my invention in part sectional elevation, 1 designates the cable and 2 the oil filled pipe or conduit therefor.

3 designates a collar surrounding the pipe 2 and welded thereto, while 4 designates a spider bolted to the collar 3.

Surrounding the insulation of the cable are barrier tubes 5 and 6 of insulation and surrounding these barrier tubes is a porcelain bushing 7, this bushing extending from one of the flanges 8 on the spider 4 upwardly adjacent the top of the structure. The bushing 7 is provided exteriorly with a plurality of petticoats 9.

Above the top of the insulating bushing 7 is a spider 10, the conductor of the cable passing through the spider as shown. The cable conductor is rigidly secured to this spider and the upper end of the bushing '7 may be sealed therein by cementing for example. The bushing 7, therefore, rests on and its lower end is sealed by the flange 8 the bushing extending between this flange and spider 10. Lateral displacement of the bushing is prevented by ring 11 bolted to The spiders 4 and 10 are held against spreading by strain insulators 12 anchored at each end to the spiders. The strain insulators are pref- 40 erably provided with turn buckles 13.

It will be seen that my invention provides a cable terminal in which the terminal is in communication with the cable pipe 2 at all times, my terminal being of great mechanical strength and capable of standing high pressures without breakdown, the spider 4 being in effect welded to the pipe 2 while the insulator '7 lies between this rigid spider and the upper spider 10 which latter is held against upward movement by the strain insulators 12. The increased strength provided by my construction is not only of value in terminating a cable but it is also useful for testing purposes where it is an advantage to place the terminal under high pressures.

The drawing shows an embodiment of my inployed, as will be understood.

placed under much higher internal pressures vention as applied to a single phase system. When my improved construction is employed for terminating a three phase system, for instance, then three potheads or terminals will be em- 69 As above mentioned my improved construction provides a structure of great mechanical strength as compared with prior devices, thereby permitting the liquid insulation of the terminal to be than heretofore possible. The increased internal pressures made possible by my improved construction increases the dielectric strength of the terminated cable and hence the surface leakage distance can be either shortened or a greater factor of safety obtained. Heretofore the permissible internal pressures have been in the neighborhood of fifteen pounds, whereas my ter= minal permits of internal pressures as high as six hundred pounds, or even.higher.

I am aware that prior to my invention termi= nals have been liquid filled and placed under some pressure say five pounds, for instance, but this pressure has been used merely to insure that the terminal is kept filled with liquid. On the other hand Ibelieve'I am the first to make use of the improved dielectric strength of the liquid in the terminal when placed under the relatively high pressures above mentioned for the purpose of either increasing the safety factor of the terminal or shortening the surface leakage distance thereof.

What I claim is:

1. A cable terminal comprising in combination an insulating bushing adapted to receive the 9p cable, a fixed member at one end of the said bushing, said member being adapted to surround the cable and sealing the end of the bushing, a second member sealing the other end of the bush ing, and insulators uniting said fixed member and said second member and resisting their separation.

2. A terminal for power cables comprising in combination an insulating bushing adapted to receive the end of the cable, a fixed spider abutting one end of said bushing and sealing the same, a second spider adapted to be afiixed to the conductor of the cable and abutting the other end of the bushing to seal the same, and strain insulators uniting said spiders and resisting their 405 separation.

3. A terminal for power cables of the type in which the cable is loosely enclosed in a pipe, said terminal comprising in combination a collar adapted to be rigidly secured to the cable pipe,

a spider rigidly secured to said collar, an insulating bushing for receiving the cable said-bushing resting on said spider and sealed thereby, a second spider abutting and sealing the other end of said, bushing, and adapted to be secured to the cable conductor, and strain insulators anchored at each end to said spiders and resisting separation of the spiders.

4. In combination an electric power cable, an oil filled pipe loosely enclosing the cable, an insulatingbushing receiving the cable and in. comvmunication with said pipe, a member at the lower end of said bushing surrounding said cable and secured liquid-tight to said pipe and bushing and sealing the lower end of the bushing, a second member at the other end of said bushing afiixed liquid-tight to the conductor of the cable and said bushing and sealing the other end of the bushing, and insulators uniting said two members and resisting their separation.

5. ,In combination an electric power cable, an oil filled pipe loosely enclosing the cable, the cable projecting from the end of said pipe, an insulating bushing in communication with said pipe surrounding the projecting portion of the cable, a fixed spider surrounding the cable and abutting one end of said bushing in a liquid-tight fashion, a second spider abutting the other end of said bushing to seal the same and aflixed to the cable conductor, and strain insulators uniting said spiders and resisting their separation.

6. In combination an electric power cable, an

enclosing member therefor, the end of the cable the spiders.

Q fill: 

